But the Jaguars running back tries not to think of the career he could have had if not for all the injuries.

“Yeah, I think about that sometimes when I’m working out, when I’m at home by myself. What if I didn’t have the second knee injury? What if I didn’t have the first? You can play that game with yourself all day, and you’ll go crazy. It is what it is. It’s life. You’ve got to take the punches, the good and the bad and just roll with it,” he said Monday as he returned to organized team activities for the first time since injuring his ankle against the Dolphins last December.

The injury, which required surgery, was the latest setback for Jones to overcome.

At Florida State, he suffered a torn anterior cruciate ligament in his right knee, a broken hand and underwent shoulder surgery. Still, he had enough potential for the Jaguars to draft him in the second round in 2004.

Then in training camp in 2006, Jones tore an ACL in his left knee and missed that season. With a torn ACL in each knee, he’s been mostly a blocking back since.

He had 42 carries in 2007, two in 2008 and four last year. He finished both of the last two seasons on injured reserve with ankle injuries, though he played in 12 games in 2008 and 13 last year.

“Like I told my wife the other night, I just want to go through a year healthy,’’ Jones said. “During the offseason, I don’t want to be in Jacksonville [rehabbing]. I don’t want to rehab. I don’t want to have any surgeries. I just want to come out of the season healthy and just win. When you’re injured and you’re on the sidelines or on the IR, it’s kind of tough.”

The Jaguars hope Jones makes it back because his blocking is integral to the success of their running game. How often they run this year may depend on whether Jones is in the game.

“A healthy Greg Jones will determine how much of a role our fullback has,” Jaguars coach Jack Del Rio said. “We think he’s a good football player, so if he’s available, we’re definitely going to use him.”

Jones was told by doctors to take it slow on his first day back, but he was just happy to be on the field.

“The past couple of months, I’ve been on the side watching everybody else run around and have a little fun out there. It’s been real good. It was a good first day for me to get my feet under me and knock some of the rust off. So today is a plus,”he said.

Del Rio is still a strong believer in Jones’ ability to make a difference for the Jaguars.

“I think when you see Greg and when Greg’s on the field and healthy, he’s one of the better blocking fullbacks in the league. He does have the ability to run as a former halfback. He does have good hands catching the ball out of the backfield. He’s got the size to match up with some of the bigger 3-4 outside linebacker rush-end type guys that we face,” Del Rio said.

Maybe it was coincidence, but the Jaguars were 7-5 in the first 12 games last season when Jones was healthy.

Then a Miami defender rolled up on Jones’ leg, injured his ankle and he didn’t play again.

The Jaguars lost that game, their final three and missed the playoffs.

Though back on the field, Jones said his speed and quickness aren’t back yet.

“I didn’t start running until probably about a month ago. These next couple of months are important to me. I’m just going to take that and work hard and do what I’ve got to do to get back on the field,” he said.

But Jones is not going to worry about getting injured again.

“I know I’m tough. I’ve battled through injuries in the past. If something is broken, it’s got to get fixed. That’s how I look at it,” he said.